Specific features of carrier transport in $n^{+}$–$n^{0}$–$n^{+}$ structures with a GaAs/AlGaAs heterojunction at ultrahigh current densities

The current–voltage characteristics of $n^{+}$–GaAs/$n^{0}$–GaAs/N$^{0}$–AlGaAs/N$^{+}$–AlGaAs/$n^{+}$–GaAs isotype heterostructures and $n^{+}$-GaAs/$n^{0}$-GaAs/$n^{+}$-GaAs homostructures are studied. It is shown that, for a heterostructure under reverse bias providing the injection of electrons from $n^0$-GaAs into $N^0$-AlGaAs, the maximum operating voltage reaches a value of 48 V at a thickness of the $N^0$-AlGaAs layer of 1.0 $\mu$m, and the current–voltage characteristic has no region of negative differential resistance. The operation of a homostructure is accompanied by a transition to the negative-differential-resistance region at a voltage of 10 V. Theoretical analysis in terms of the energy-balance model demonstrated that the reverse-biased isotype heterostructure has no negative-differential-resistance region because, in this case, the field domain does not collapse in contrast to what occurs in homostructures.